Effects of sewage sludge and sewage sludge compost amendment on soil properties and zea mays l. plants (heavy metals, quality and productivity)

The use of organic wastes in agriculture can improve the soil's productive capacity, and physical and chemical characteristics. This study evaluated the effects of sewage sludge, sewage sludge compost and inorganic fertilizer applications on nickel, copper and zinc contents in soil and corn grains (Zea mays L); maize productivity, and grain nutritional quality. Sewage sludge and sewage sludge compost at 18 Mg ha¿1 and a mineral fertilizer (N-P-K) with a formulation of 150-75-30 were applied. Significant differences were observed in organic matter, phosphorus and zinc content between sewage sludge-soil and compost-soil, and inorganic fertilizer-soil (P < 0.05). Copper concentration was significantly high in compost-soil (P < 0.05). Productivity in compost-soil and sewage sludge-soil mixtures was higher than in inorganic fertilizer-soil. Grain quality, measured by relative percentage of starch, total nitrogen, protein, acid detergent fiber and neutral detergent fiber were adequate for human consumption. Application of sewage sludge or compost did not increase heavy metal concentrations in grain with respect to inorganic fertilizer-soil.